The present invention relates to the generation and delivery of sterile water. It finds particular application in medical applications and in the decontamination arts. It should be appreciated, however, that the invention is also applicable to other systems where a source of sterile water is employed.
High purity water, which is free of microorganisms and other contaminants, is desirable for a variety of medical, scientific, and pharmaceutical applications, including the formulation of intravenous solutions, irrigation during surgery, rinsing of sterilized equipment, and the like.
Sterile water is used in hospitals to prepare various solutions for many other purposes. To avoid shipment of large quantities of these solutions, it is desirable to have a generator which supplies sterile water on site in the hospital, ready for the dilution of dehydrated formulations, as needed. For field emergency support applications, it is preferable that the sterile water generator be readily portable, and have a low power consumption.
In dental applications, water is used to feed dental handpieces, such as drills, or to supply mouth rinse devices. The supply lines to such equipment are often long, resulting in propagation of waterborne pathogens during periods of inactivity. Such pathogens may be harmful to patients, especially during invasive procedures. Accordingly, it is desirable that the water supplied to the devices be free of pathogens. An on-site sterile water generator which is capable of delivering sterile water on demand is thus desirable.
A variety of sterilization and disinfection processes include a rinse cycle for rinsing items, such as medical and pharmaceutical devices, and the like, after decontamination. Automated sterilization systems have been developed in which a premeasured dose of a decontaminant, such as peracetic acid or other strong oxidant, is circulated in solution through the system. Examples of such systems are disclosed in U.S. Pat. Nos. 4,892,706 and 5,217,698. Items to be decontaminated are inserted into a receiving tray of the system and a cartridge of concentrated decontaminant is inserted into a well of the system. As water flows through the system, the decontaminant is diluted and carried to the receiving tray. At the end of the decontamination cycle, the decontaminant solution is disposed of and a rinse fluid is circulated through the system to remove traces of the decontaminant, detergents, minerals, or other residue from the system and from the decontaminated items.
To avoid recontamination of the items, the rinse fluid is preferably free of microorganisms. Tap water may contain 103 microorganisms/ml. Thus, rinsing the decontaminated items with tap water can lead to recontamination of the items. Filters are often used to remove particles down to about 0.2 microns in diameter. Such filters have been useful in removing harmful organisms. However, tap water may contain undesirable substances that are below 0.2 microns, such as dissolved minerals, organic based substances, volatile solvents, and other potentially toxic or otherwise undesirable substances. Additionally, it has recently been found that some water systems may even have live viruses, spores, or other living organisms below 0.2 microns in size.
Filter elements typically include a pleated material for filtering the particles from water. Once microbial growth propagates into the pleated region of the filter element, it is difficult to sterilize the element with liquid sterilizing agents on the filtered side, due to concentration gradients between the water supply side and chemicals on the filtered water side. Filtered material builds up on the filter and slows the flow rate of water through the filter. The filter is, therefore, replaced periodically. Contaminants tend to enter the filtered side during the replacement process. It is therefore desirable to sterilize in place the filter and associated piping after filter replacement.
The present invention provides a new and improved sterile water generator and a method for sterilizing and maintaining a sterile pathway, which overcome the above-referenced problems and others.
In accordance with one aspect of the present invention, a sterile water generator is provided. The generator includes a water heater which receives incoming water and heats the water to a sufficient temperature to sterilize the water and presterilize a pathway for delivering the sterile water from the water heater to a site at which the sterile water is to be used, the presterilized pathway being sterilized along at least a portion of its length by high temperature water or steam from the water heater.
In accordance with another aspect of the present invention, a method of supplying sterile water through a sterile fluid pathway is provided. A first sterilizing fluid is passed along a first portion of the sterile fluid pathway to effect sterilization. A liquid is heated to generate a second sterilizing fluid. The second sterilizing fluid is passed along at least a second portion of a fluid pathway to effect sterilization of the second portion of the pathway. The first and second portions have at least one common element over which both fluids pass. Sterile water is subsequently passed along the sterile fluid pathway.
In accordance with another aspect of the present invention, a method of decontamination is provided. The method includes contacting items to be decontaminated with a decontaminant fluid and contacting the decontaminated items with a rinse fluid, the rinse fluid including water which has been heated to a sufficient temperature to sterilize the water.
In accordance with another aspect of the present invention, a decontamination system is provided. The system includes a vessel for receiving items to be sterilized. A source of wan antimicrobial agent is connected with the vessel and supplies the antimicrobial agent to the vessel for decontaminating the items in the vessel. A sterile water generator is connected with the vessel and supplies sterile rinse water to the vessel for rinsing the decontaminated items.
One advantage of the present invention is that sterile water is generated in a short period of time following commencement of heating of incoming tap water.
Another advantage of the present invention is in the provision of injection quality sterile water.
Another advantage of the present invention resides in its energy efficiency. Heat used in sterilizing the water is reclaimed by the incoming tap water.
Yet another advantage of the present invention is that the fluid pathways between the generator and the system in which the water is to be used are sterilized or pasteurized with steam or heated sterile water prior to passage of the sterile water therethrough.
A further advantage of the present invention is that water hardness salts are changed into solid form minimizing deposition on items rinsed as an integral part of the water sterilization process in the sterile water generating system.
A still further advantage of the present invention is the provision of a sterile sampling port for verifying the sterility of sterile water generated.
Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments.